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<title>Network/Wai/Middleware/Rewrite.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE OverloadedStrings #-}</span>
<a name="line-2"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Network</span><span class='hs-varop'>.</span><span class='hs-conid'>Wai</span><span class='hs-varop'>.</span><span class='hs-conid'>Middleware</span><span class='hs-varop'>.</span><span class='hs-conid'>Rewrite</span>
<a name="line-3"></a> <span class='hs-layout'>(</span> <span class='hs-varid'>rewrite</span><span class='hs-layout'>,</span> <span class='hs-varid'>autoHtmlRewrite</span>
<a name="line-4"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-5"></a>
<a name="line-6"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Network</span><span class='hs-varop'>.</span><span class='hs-conid'>Wai</span>
<a name="line-7"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Directory</span> <span class='hs-layout'>(</span><span class='hs-varid'>doesFileExist</span><span class='hs-layout'>)</span>
<a name="line-8"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftIO</span><span class='hs-layout'>)</span>
<a name="line-9"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Text</span> <span class='hs-layout'>(</span><span class='hs-conid'>Text</span><span class='hs-layout'>,</span> <span class='hs-varid'>unpack</span><span class='hs-layout'>,</span> <span class='hs-varid'>pack</span><span class='hs-layout'>)</span>
<a name="line-10"></a>
<a name="line-11"></a><a name="rewrite"></a><span class='hs-comment'>-- | rewrite based on your own conversion rules</span>
<a name="line-12"></a><span class='hs-comment'>-- Example usage: rewrite (autoHtmlRewrite "static")</span>
<a name="line-13"></a><span class='hs-definition'>rewrite</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Text</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Text</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Middleware</span>
<a name="line-14"></a><span class='hs-definition'>rewrite</span> <span class='hs-varid'>convert</span> <span class='hs-varid'>app</span> <span class='hs-varid'>req</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-15"></a> <span class='hs-varid'>newPathInfo</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>liftIO</span> <span class='hs-varop'>$</span> <span class='hs-varid'>convert</span> <span class='hs-varop'>$</span> <span class='hs-varid'>pathInfo</span> <span class='hs-varid'>req</span>
<a name="line-16"></a> <span class='hs-varid'>app</span> <span class='hs-varid'>req</span> <span class='hs-layout'>{</span> <span class='hs-varid'>pathInfo</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>newPathInfo</span> <span class='hs-layout'>}</span>
<a name="line-17"></a>
<a name="line-18"></a><a name="autoHtmlRewrite"></a><span class='hs-comment'>-- | example rewriter</span>
<a name="line-19"></a><span class='hs-comment'>-- implements 2 rules for static html re-writes</span>
<a name="line-20"></a><span class='hs-comment'>-- 1) for a directory foo/, check for foo/index.html</span>
<a name="line-21"></a><span class='hs-comment'>-- 2) for a non-directory bar, check for bar.html</span>
<a name="line-22"></a><span class='hs-comment'>-- if the file exists, do the rewrite</span>
<a name="line-23"></a><span class='hs-definition'>autoHtmlRewrite</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Text</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Text</span><span class='hs-keyglyph'>]</span>
<a name="line-24"></a><span class='hs-definition'>autoHtmlRewrite</span> <span class='hs-varid'>staticDir</span> <span class='hs-varid'>pieces'</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-25"></a> <span class='hs-varid'>fe</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doesFileExist</span> <span class='hs-varop'>$</span> <span class='hs-varid'>staticDir</span> <span class='hs-varop'>++</span> <span class='hs-str'>"/"</span> <span class='hs-varop'>++</span> <span class='hs-varid'>reWritePath</span>
<a name="line-26"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>fe</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>map</span> <span class='hs-varid'>pack</span> <span class='hs-varid'>reWritePieces</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>pieces'</span>
<a name="line-27"></a> <span class='hs-keyword'>where</span>
<a name="line-28"></a> <span class='hs-varid'>pieces</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>unpack</span> <span class='hs-varid'>pieces'</span>
<a name="line-29"></a> <span class='hs-varid'>reWritePath</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concat</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conop'>:</span><span class='hs-layout'>)</span> <span class='hs-chr'>'/'</span><span class='hs-layout'>)</span> <span class='hs-varid'>reWritePieces</span>
<a name="line-30"></a> <span class='hs-varid'>reWritePieces</span> <span class='hs-keyglyph'>=</span>
<a name="line-31"></a> <span class='hs-keyword'>if</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>pieces</span><span class='hs-layout'>)</span> <span class='hs-varop'>||</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varop'>$</span> <span class='hs-varid'>last</span> <span class='hs-varid'>pieces</span><span class='hs-layout'>)</span>
<a name="line-32"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>pieces</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-str'>"index.html"</span><span class='hs-keyglyph'>]</span>
<a name="line-33"></a> <span class='hs-keyword'>else</span> <span class='hs-layout'>(</span><span class='hs-varid'>init</span> <span class='hs-varid'>pieces</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>last</span> <span class='hs-varid'>pieces</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span> <span class='hs-str'>".html"</span><span class='hs-keyglyph'>]</span>
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